Connector with fluid pressure relief devices



S. OKTAY Jan. 30, 1968 CONNECTOR WITH FLUID PRESSURE RELIEF DEVICES I 2 Sheets-5heet Filed July 15, 1966 FIG. 3

FIG.2

FIG.1

FIG.6

FIG.5

FIG.4

INVILNIUR. SEVGIN OKTAY ATTORNEY CONNECTOR WITH FLUID PRESSURE RELIEF DEVICES Filed July 15, 1966 S. OKTAY Jan. 30, 1968 2 Sheets-Sheet 2 United States Patent 3,366,916 (IONNECTOR WITH FLUID PRESSURE RELIEF DEVICES Sevgin Olrtay, Beacon, N.Y., assignor to International Business Machines Corporation, Armonk, N.Y., a

corporation of New York Filed July 15, 1966, Ser. No. 565,503 8 Claims. (Cl. 33974) The present invention relates in general to an electrical connector device and more particularly to a hydraulically or pneumatically controlled release device for spring contacts to allow easy insertion of plugs or printed circuit cards and still preserve high uniform contact pressure and low uniform resistance at contact connections.

In the prior art, socket plug and card receivers with resilient spring contact fingers are often poorly designed as a compromise between the pressures that the spring fingers should exert and the lower pressures actually used because of difficulty of plug insertion. When multiple contacts cooperate with a series of plug pins or an array of card terminals, the pressures become additive and offer too much resistance to hand insertion unless the contacts re made weaker than the best electrical design dictates, especially for low power applications. A remedy is sometimes sought to provide relatively high contact pressure between contact members by utilizing a cam or eccentrically mounted roller. However, the close tolerances required for machining cams and the diificulty resulting from angular displacement of cam members or cam member wear, limits the utility of this approach. In addition, it is difficult to maintain uniform contact pressure between the individual contacts aligned in a multi-contact assembly,

In view of the foregoing, it is apparent that there is need for a style of connector which allows low insertion and removal force and yet provides high uniform pressure of contacts against inserted terminals.

The present invention relates to electrical socket reeivers for printed circuit cards or pins of a type that permits initial insertion to be made under slight or no pressure and a substantial amount of contact pressure to be later applied after the printed circuit card is fully inserted. Heretofore, in the usual printed circuit or plug socket receiver, pairs of spring contact blades were arranged to pinch initially and directly the inserted card or pin between them and establish contact with the edge terminals of the card, and such pinching exerted quite an amount of resistance to the insertion and retraction of the card. Now such direct pinching is avoided. In the present instance an expansible tube is mounted between such contact fingers and is filled with fluid or air under selective pressure to expand it and spread the contacts apart before the card is inserted and then the tubing is collapsed or deflated to allow the contacts to exert their normal high mechanical pressure. After the card is inserted, a good electrical connection is established and the card is held in place by means of the spring-loaded contact elements. When removal of the card from the connector is desired, the flexible tube with one end closed and which may be termed a fluid key is moved into position in a cavity along the length of the connector between the contacts and then the open end of the fluid key is compressed by a hand bulb or connected to a pressure tank so that the fluid pressure expands the tubing or key for an amount suflicient to push the contact elements apart and release the card for removal by hand. Then the card may be removed Without any friction or sliding motion or wear between the contact surfaces on the card and the spring contact terminal ends. After the card has been removed, another card or the same card may be re-inserted into place. When once inserted, the pressure is removed from the air or fluid key and the tubing collapsed so that the contact elements again exert pressure against the card. These contact elements may be designed, arranged and proportioned so that there is optionally a slight wiping movement against the card terminals to remove dirt or oxide upon card insertion, but the main pressure for resisting the insertion of the card is not present.

There are some forms of pneumatic and fluid pressure applicators in the electrical connector art, but they are of the form for exerting pressure in the reverse of the style shown here because they propose pressure to force contacts against a card or pin, while the present fluid pressure means serves to spread the contacts away from the inserted member rather than to exert the pressure upon the member. In other words, the prior art is concerned with the normal continuous application of pressure all the time while the devices are in use, while the present invention relates to use of pressure at brief intervals for replacement and repair and at a time other than the time of the usage of the connector.

Accordingly, a primary object of the present invention is to provide an improved electrical connector.

Another object of the present invention is to provide a pressure controlled connector for relieving contact pressure between an insertible device and multi-contact electrical members.

Another object of the present invention is to provide a pneumatically or hydraulically controlled connector for relieving contact pressure between individual electrical contact numbers and restoring uniform contact pressure when the devices are to be put in usage.

Still another object of the present invention is to provide an improved multiple contact electrical connector assembly having low insertion and removal resistance to inserted pin or card elements and adapted to provide a high uniform contact pressure exerted by all the individual flexible contacts of the assembly.

Another object of the present invention is to provide an improved pluggable unit assembly comprising a long socket receiver and an insertible printed circuit card, said improved assembly being adapted to provide low and uniform electrical contact resistance between the contact fingers or members of the socket and the conductor terminal strips of the printed circuit card.

Another object of the invention is to provide a contact spreader for insertion into a connector socket receiver for spreading the contacts therein to ease the insertion of pins or cards for cooperation with the electrical devices of the socket.

Another object of the invention is to provide a portable manually operable contact spreader for a computer operators use or a servicemans kit to aid in removal of connector assemblies in general, and printed circuit cards, wafers, boards, circuits and pin boards in particular.

Another object of the invention is to so design single and dual spring contacts of multiple contact arrays and columnar arrangements with a configuration such as to receive an expansible contact opener to be easily inserted and removed.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose by Way of examples the principle of the invention and the best mode which has been contemplated of applying that principle.

In the drawings:

FIG. 1 is a sectional elevation view taken through a socket receiver and showing an expansible contact spreader as a tube inserted but not inflated.

FIG. 2 is a sectional elevation view of the same socket 3 showing the contact spreader distended or inflated to spread the contacts and allow the printed circuit board to be inserted easily.

FIG. 3 illustrates the third stage of the operation of the same socket as shown in FIGS. 1 and 2 in a sectional view wherein the expansible tubing has been removed and the spring fingers exert normal pressure against the terminal areas of the inserted printed circuit card.

FIG. 4 is an elevation view partly in section showing a pin socket receiver wherein a rectangular expansible contact spreader is inserted before being inflated.

FIG. 5 shows the same pin receiver in sectional elevation wherein the rectangular flexible contact spreader is inflated or distended to spread the spring contacts apart permitting easy insertion of the contact pins.

FIG. 6 is a sectional elevation view of the same socket receiver shown in FIGS. 4 and 5 but wherein the rectangular expansion member has been deflated or collapsed and removed to allow the spring fingers to assume their normal pressure positions against the inserted pins to establish good electrical contact.

FIG. 7 is a perspective view showing a simple form of fluid key or contact spreader comprising a length of closed rubber tubing terminating in a hand operated air pressure bulb. The operating end of the tubing is shown inserted into a socket of the kind illustrated in FIGS. 1-3.

Summarizing the invention, it may be noted that it involves a novel method of operating an electrical connector or socket receiver by first inserting a pressure exerting member, applying pressure to said member to spread the socket receiver contacts, easily inserting a plug or card, collapsing the pressure member to allow normal high pressure contact to be established and,

finally withdrawing the pressure member.

Referring now to the drawings and more particularly to FIG. 1 thereof, it is seen that an example of a connector comprises a plastic housing or outer chamber having an inner recessed portion containing a liner 21 for limiting the motion of the pairs of spring fingers 22 and 23, the lower ends of which are embedded in the housing and liner, and the upper ends 24 and 25 which extend as flexible contact-establishing portions being rounded to receive and exert pressure against an inserted member such as an inserted printer circuit card 28,- having regularly spaced conductive terminal areas 29 formed as printed circuit portions adhering to both faces of the circuit card or board member 28. It is understood that the housing 20 and liner 21 are of any form of insulation sufficient to provide the strength necessary to support a whole line or series of pairs of the terminal spring fingers, such as 22 and 23. Although only a sectional view is shown in FIG. 1, it is understood that the type of, construction shown may be multiplied dozens or scores of times for a full length of a long receiver for establishing electrical connections to many printed circuit terminal areas and also carry circuits in and out of such areas by connections made at the lower ends 22 and 23 of the multiple sets of pairs of spring fingers available on the outside of the housing 20 for solder connections, etc.

Returning to consideration of the spring fingers 22 and 23, it is to be realized that they are usually of some spring or resilient metal such as beryllium copper or Phosphor bronze and formed as shown with an enlarged or bowed center area 30, which is the receiver for the expansible, central flexible cylindrical fluid member 26. As shown in FIG. 1, the tube member 26 has a small central opening 27 which is a cylindrical opening suited to receive air or fluid to be put under pressure to expand. Tube 26 is understood to be long and cylindrical and to extend the full length of a socket receiver, i.e., running through the center 30 of many pairs of contact spring fingers of flexible conductive material such asthose indicated by reference numerals 22 and 23. As shown in FIG. 1, the expansible cylinder 26 is shown in the collapsed condition 4 with the central cylindrical area 27 constricted and of small dimensions, and it is in this area that the pneumatic or hydraulic fluid is present to exert the necessary expanding pressure when desired. It may be noted here that the end portion or plug 17 (FIG. 7) of the liner 21 is formed with a cylindrical opening proportioned to receive the expansible member 26 in a central position to be inserted for the full length of the socket receiver. In FIG. 1 it is also shown that the spring fingers 22 and 23 are shaped with centrally located arcuate or bowed portions 30 suited to receive the tube with clearance when it is collapsed.

As shown in FIG. 2, the pressure member 26 is distended and expanded by the fluid contents thereof being put under pressure and there results the expansion of the tube 26, as made indent by referring to the difference between the diameter of the same member in FIG. 1 as contrasted with the showing in FIG. 2.

The expanding tubing 26 is to be made of a flexible material, such as gum rubber or neoprene or any other natural or artifical rubber-like material suitable to be expanded double or more its original size and return to the original shape. As shown in FIG. 2 with the tubing expanded, it will be noted that it presses against the inner faces of the spring fingers 22 and 23 at 30 to such a degree that the upper contact establishing ends 24 and 25 are separated to such an extent that the printed circuit board 28 may be rather freely inserted with the terminal areas 29 thereon freely passing between the ends 24 and 25 or merely rubbing dirt off in a wiping motion.

The extent of expansion of the cylindrical member 26 is proportioned according to the desired kind of wiping or non-wiping insertion of the printed circuit board 28. For certain applications it would be advisable that the terminal areas on the printed circuit board be somewhat abraded to remove oxides by the extending spring finger ends 24 and 25, as it is inserted without too much forceful resistance being ofifered; and, on the other hand, for other applications with gold plating for example it would be desirable that the spring fingers ends 24 and 25 be fully separated to offer no resistance at all for the insertion of the board or pin. It is understood that the board 28 will have some form of stops in cooperation therewith on both ends of the socket receiver so that an accurate fully depressed position is established. These are not shown in the views as being understood to be part of the usual provisions of socket receivers.

Although a regular series of operations is illustrated from left to right in FIGS. 1, 2 and 3, there is a pair of operations not illustrated between FIG. 2 and FIG. 3. They involve the collapsing of the expanding tube member 26 and its withdrawal after the insertion of the card as shown in FIG. 2. After these intermediate operations have been performed, then the socket contents assume the positions shown in FIG. 3. There it is noted that the inner bowed formations 30 of the spring fingers, no longer contain the expanding tube member 26; and the upper ends 24 and 25 of the spring fingers are fully engaged with the terminal areas 29 of the printed circuit board 28. This is the normal position of all the parts while the machine is in the operating condition. Then there is a high pressure contact by the spring fingers exerted against the board terminal areas to insure good electrical connections and low electrical resistance between the various connections made to and from the spring fingers 22 and 23.

Although it is stated that the expanding member 26 is withdrawn for the contacts to assume the normal operating position as shown in FIG. 3, it will be realized that the expanding member may be retained in position and collapsed as shown in FIG. 1, and there is no essential need for withdrawing such a member other than the fact that it may be handy to be used in another position on the machine.

When it is desired to remove the printed circuit board 28 for inspection or replacement, then the, expanding member 26 is again inserted or, if ordinarily left in place, it is merely expanded to the position shown in FIG. 2 whereby the spring fingers are pressed apart and then the board 28 may be easily removed.

In order to remove the printed circuit card 28 from the connector in a vacuum type operation, a low fluid pressure within the fluid key 26 as a vacuum condition may be eliminated or substantially reduced, thereby restoring the contacts to their wide open position and permitting removal of the printed card with a nominal removal force. As an alternative to application of normal pressure and greater pressure, normal pressure and a vacuum may be applied to cause the flexible tubing to collapse into the one of two positions. In this manner, low insertion and removal forces and a reliable uniform contact between the individual contact members may be provided. While a pneumatically operated arrangement has been described in the preferred embodiment, it will be apparent to one skilled in the art that a hydraulically actuated arrangement may be substituted and employed.

Although one application of the invention is illustrated in FIGS. 1, 2 and 3 as a receiver for a printed circuit card, it will be realized that many other forms of receivers may be actuated by means of the internal expanding fluid holder as illustrated, and another variation may be of the form wherein pins are extended as a form of plug into a socket receiver and it is such a form of device which is about to be considered in conjunction with FIGS. 4, 5 and 6.

Referring to FIG. 4, it is seen that a pin receiver housing 38 may be formed with an internal opening and have embedded therein one pair 39 and 40 of a whole series of longitudinally arranged pairs of projecting pins for insertion into a main panel board. Attached internally to the inner ends of the pins 39 and 40 are spring contact members 41 and 42, each formed with a curved pin contact section such as 43 and 44 and each formed with a sheet metal flange 49 having vertical offset lugs 45 and 46.

These lugs are oppositely spaced and arranged face to face with a space between them in which is present a rectangular, flexible, expansible tube 47 having a normal narrow opening or central conduit 48.

Suited to be inserted in the socket 38 is an electronic unit instrumentality 35 formed with a dependent pair of connector pins 36 and 37 which are to be inserted in a pair of upper openings in the housing 38 and into cooperation with the curved formations 43 and 44 formed on the spring fingers 41 and 42. As shown in FIG. 4, without any aid for insertion it would be rather difficult for the pins 36 and 37 to cam the two spring fingers 41 and 42 out to a widely open position so that the pins 36 and 37 may be fully depressed. However, to aid such an insertion, the flexible, rectangularly sectioned expansible member 47 is adapted to be distended by pneumatic or hydraulic pressure to aid in such an insertion as shown in FIG. 5. There it is seen that the central opening 48 of the rectangular section 47 is greatly distended and, in being so distended, pushes against the side lugs 45 and 46 of the spring fingers and moves them outwardly to such an extent that their flange formations are pushed against the walls of the inner opening of the housing 38. When the spring fingers 41 and 42 are so positioned in an opened formation, it is readily observed that the pins 36 and 37 find it possible to be freely depressed and inserted in such a position where they are readily engaged by the curved formations 43 and 44 of the spring fingers once the pressure member 47 is collapsed and withdrawn as shown in FIG. 6.

Here again, as was the case with FIG. 3, in FIG. 6 it is possible that the collapsed expansible member 47 may remain present if desired and as such would not interfere with the electrical engagement and contact characteristics of the connector. When it is desired to remove the electrical implement 35 and pull upwardly on the pins 36 and 37, it is then made easier for such extraction by inserting the expansible tubing 47 and distending it by pressure of air of hydraulic fluid to again cause the parts to assume the position of FIG. 5 wherein the part 35 may be extracted and a substitute therefor re-inserted.

Although the invention is illustrated in conjunction with pairs of facing spring fingers, it will be realized that the construction is eflective in conjunction with a single alignment of spring fingers such as 25, FIG. 1, to the exclusion of a companion finger 24. In such a form of construction the inserted board 28 may assume the configuration of a flexible, flat cable whereon there is a single set of spaced lines having terminal areas such as areas of conductive material 29. In all of these forms of socket receivers it is assumed that a whole alignment array or a columnar series of pairs of contacts 22, 23 are evenly arranged and spaced to conform with the cooperating inserted member and the progression of terminal areas 29.

In FIG. 7, an elemental form of a complete expansible member or fluid key 26 is illustrated, as assembled within a socket assembly of the kind shown in FIGS. l3. There it is seen that the hollow cyclinder 26- shown in FIG. 1 is of substantial length and has a closed end 50. At the end opposite to the closed end of the piece of gum rubber tubing or other flexible material, is a valve connection 52 to a pressure applicator, such as a hand bulb 51. A hand-operated pressure applicator, such as shown in FIG. 7, is effective for short lengths of socket receivers. However, should it be required that the tubing 26 be of substantial length and perhaps even coiled back and forth through a series of socket receivers, then some further pressure applicating means may be provided to the valve formation 52 in the form of something like a foot treadle or the bulb or a pressure cartridge or tank, or in cases of requirements of extreme pressure there be some form of air or fluid pump connected to the valve structure 52. On the key there is shown a stiffening elbow 53 for the tube 26 and a centralizing socket end plug 17 which fits into the end of housing 20 and may be secured in position by a spline pin 54 which is forced into and through openings 55 and 56 in the parts.

As shown in FIG. 7, the type of bulb 51 and valve 52 may be of the form commonly used in medical practice to measure blood pressure by the application of air pressure to act on arm band bags. In the present instance, although tubing 26 is of a soft, flexible and expansible material, yet it is of suflicient stiffness to permit ready insertion between the bowed centers 30 of a substantial length of columnar array of facing contacts, such as those of the contact fingers 22 and 23 of FIG. 1.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to preferred embodiments, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit and scope of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A method for inserting a circuit element into a socket receiver with a resiliently flexible contact comprising the steps of;

forcing said contact aside by fluid pressure,

inserting said element, and

removing said fluid pressure to allow said contact to press against and establish firm electrical contact with said inserted element.

2. A method of removing a circuit element from a socket receiver with a resiliently flexible contact pressing against said element comprising the steps of;

inserting a fluid pressure applicator next to said contact,

expanding said applicator by fluid pressure to force said contact away from said circuit element, and removing the free circuit element.

3. A method for inserting and removing a circuit element in a socket receiver with a resiliently flexible contact cooperating with the circuit element comprising the steps of applying a vacuum to collapse an expanded fluid applicator,

inserting said collapsed applicator next to said resiliently flexible contact,

removing said vacuum etfect to allow said collapsed applicator to expand next to said contact and force it aside,

inserting said element, and

again applying the vacuum to collapse the expanded fluid applicator, whereby said applicator in a collapsed condition allows the free contact to press against and establish firm electrical contact with said inserted element.

4. A pressure actuated electrical connector assembly comprising in combination an electronic unit having a plurality of conductor pins thereon, a socket member comprising a recessed body portion of insulating material, a plurality of resiliently flexible contact members corresponding in number and position to the conductor pins on said unittwithin said recess, each of said contact members including a pair of opposed finger members electrically separated,

a section of tubing, said tubing being threaded between each of said pairs of contact members, and

means for applying fluid pressure to said tubing whereby the resultant expansion of said tubing forces said contact members away from the adjacent conductor pins on said electronic unit to thereby provide ease of withdrawal and insertion of the unit.

5. A pressure actuated electrical connector, as claimed in claim 4, in which said last mentioned means comprises a manipulative air pressure bulb.

6. An electrical assembly for supporting a printed circuit card and providing low resistance connections between contacts of said assembly an-d conductor strips on said printed circuit card comprising a socket member of insulating material having a recessed portion therein, a contact assembly positioned within said recessed portion, said contact assembly comprising a plurality of resiliently flexible contacts, each of said contacts having a pair of opposed contact fingers in low resistance wiping relationship with said conductor strips during insertion of said printed circuit card,

an expansible means having a pressure fluid cavity,

said expansible means being disposed between related pairs of said contacts of said plurality of contacts so as to widen the space between said contacts and push them away from the conductor strips of said printed circuit card when the pressure in said pressure fluid cavity is increased, whereby the printed circuit card may be withdrawn and inserted with a desired amount of nominal force.

7. A connector assembly for providing high contact pressure and low uniform resistance between a plurality of contacts and corresponding conductor strips on a printed circuit card comprising a body of insulating ma terial having an inner recessed portion,

a longitudinally extending contact assembly mounted within said recessed portion, said contact assembly comprising a plurality of resiliently flexible contacts, each of said contacts including a pair of opposed finger members,

means for securing said contact assembly within said recessed portion, and

a portable manually operable expansible means having a pressure fluid cavity, said expansible means being insertible between all of said pairs of finger members to force all of said finger members away from contact with the associated conductor strips upon expansion of the expansible member by fluid pressure exerted manipulatively.

8. A multiple contact connector assembly for providing high contact pressure and low and substantially uniform contact resistance between the individual contacts of said assembly and conductor strips on a printed circuit card comprising a recessed body of insulating material,

a plurality of resiliently flexible contact members within said recess, each contact member comprising a pair of opposed bowed finger members connected to separate terminals,

a lining means mounted behind adjacent contact members, said lining means having contoured portions on the sides thereof to act as stops to confine the finger members of adjacent contacts,

an end portion, said end portion being recessed centrally to align an opening with the central space between bowed portions of said finger members,

a tubing member threaded between said bowed finger members and through said end portion,

pressure means to expand said tubing member, thereby forcing said contact members away from the adjacent conductor strips of said printed circuit card, whereby a card may be easily inserted and withdrawn with a desired minimum amount of wiping insertion pressure, and

relaxation of said pressure in said tubing member causing said finger members to assume a contact closing position exerting high contact pressure against the strips on the printed circuit card.

References Cited UNITED STATES PATENTS 348,868 9/1886 Straube -625 520,226 5/ 1894 Weyhe 49477 2,796,271 6/1957 Darmstadter 60-625 2,975,390 3/1961 Cardascia et al. 339-117 XR 2,978,666 4/1961 McGregor 339-117 XR 3,076,166 1/1963 Raddin 339-117 XR FOREIGN PATENTS 885,040 12/1961 Great Britain.

I. H. MCGLYNN, Assistant Examiner. 

4. A PRESSURE ACTUATED ELECTRICAL CONNECTOR ASSEMBLY COMPRISING IN COMBINATION AN ELECTRONIC UNIT HAVING A PLURALITY OF CONDUCTOR PINS THEREON, A SOCKET MEMBER COMPRISING A RECESSED BODY PORTION OF INSULATING MATERIAL, A PLURALITY OF RESILIENTLY FLEXIBLE CONTACT MEMBERS CORRESPONDING IN NUMBER AND POSITION TO THE CONDUCTOR PINS ON SAID UNIT WITHIN SAID RECESSES, EACH OF SAID CONTACT MEMBERS INCLUDING A PAIR OF OPPOSED FINGER MEMBERS ELECTRICALLY SEPARATED, A SECTION OF TUBING, SAID TUBING BEING THREADED BETWEEN EACH FOR APPLYING OF CONTACT MEMBERS, AND MEANS FOR APPLYING FLUID PRESSURE TO SAID TUBING WHEREBY THE RESULTANT EXPANSION OF SAID TUBING FORCES AND CONTACT MEMBERS AWAY FROM THE ADJACENT CONDUCTOR PINS ON SAID ELECTRONIC UNIT TO THEREBY PROVIDE EASE OF WITHDRAWAL AND INSERTION OF THE UNIT. 